Tartaric acid and polyphenols recovery from winery waste lees using membrane separation processes”, Journal of Chemical Technology and Biotechnology
Wine waste lees are currently partly exploited for tartaric acid (TA) production, through an environment-offensive process, while concurrently occurring bio-active polyphenolic compounds are wasted. This paper, deals with the development of an integrated, environment friendly process, using mild conditions, for recovering TA with simultaneous exploitation of total polyphenols (TPP) from wine lees. A first process step, described in a previous publication, yields a liquid stream containing approx. 44.2 g L−1 TA and 323.3mg GAE L−1 TPP. In the present study, various ultrafiltration and nanofiltration membranes are assessed, in bench-scale filtration tests, for their efficiency in separating the two main products (i.e. TA and TPP) from this stream. The most promising process configurations are also tested in a laboratory-scale cross-flow membrane filtration pilot plant and assessed concerning the separation efficiency and the membrane filtration performance, to determine process feasibility at industrial scale. The results show that a nanofiltration membrane with typical pore size approx. 1 kDa exhibits satisfactory separation and low-fouling filtration performance. The permeate, containing the bulk of TA(approx. 42.6 g L−1) could be used for TA recovery, whereas the concentrate, with antioxidant activity (EC50 = 10.0mg sample mg−1 DPPH.), could be further purified to obtain polyphenolic-rich formulations.